First Record: a Stem and Bulb Plant Parasitic Nematode at Garlic Area Centre Temanggung, Central Java, Indonesia with Species Reference to Ditylenchus Dipsaci

A survey to investigate the stem and bulb plant parasitic nematode at one of garlic area centre, in Temanggung, Central Java, Indonesia was conducted from Januaryto February 2018. Infected plant with specific symptoms, morphological and morphometric characters both of female and male of adult nematodes were used to describe a A1 quarantine plant parasitic nematode Ditylenchus dipsaci. Seven from nine observed locations were postively infected with population in average 2.67 nematodes per 100 g of soil and 2.67–189.33 per bulb. This is the first report of D. dipsaci from Indonesia and consequently further investigations were needed to know their distribution and also to confirm the origin of the nematode. IntisariSurvei keberadaan nematoda parasit batang dan umbi dilakukan pada bulan Januari–Februari 2018 pada satu sentra penangkaran bawang putih di Temanggung, Jawa Tengah, Indonesia. Tanaman terinfeksi dengan gejala serangan yang spesifik, karakter morfologi dan morfometri nematoda betina dan jantan dewasa dipergunakan dalam identifikasi Ditylenchus dipsaci yang merupakan nematoda parasit tanaman yang termasuk OPTK A1 (Organisme Pengganggu Tanaman Karantina A1) di Indonesia. Sebanyak tujuh dari sembilan lokasi yang diamati mengindikasikan positif sebagai daerah sebaran nematoda tersebut dengan populasi rata-rata 2,67 ekor per 100 gram tanah dan 2,67–189,33 nematoda per umbi. Laporan pertama tentang nematoda D. dipsaci ini membawa konsekuensi perlunya penelitian lebih lanjut untuk mengetahui daerah sebaran dan juga konfirmasi dari mana nematoda tersebut berasal.


INTRODUCTION
A stem and bulb nematodes, Ditylenchus dipsaci (Tylenchida: Anguinidae), are a destructive plant parasitic nematode of many vegetables, especially of garlic and onion. They attack mainly on the root, tubers and stems of the host plant. Heavily attacked plants cause stunted growth, yellowing and twisting leaves and defoliation and effect to crop losses of 60-80%. The infected onion bulbs are also a means of spreading the nematodes becoming more widespread (Yavuzaslanoglu et al., 2015). The stem and bulb nematode Ditylenchus dipsaci has placed on the Quarantine Pest A1 List in Indonesia and it is regulated as a quarantine pest.
Life cycle of D. dipsaci average in 19−23 days. Mature females deposit eggs during 20−50 days and about 10 eggs/day. Under favorable conditions, the second stage juveniles hatch from the eggs and undergo two molts become the fourth juveniles and infective stage. These juveniles can penetrate and feed on young tissues of leaves, stems, bulbs, and other plant parts, but generally not roots. The fourthstage juveniles go through the fourth molt and differentiate into mature males and females and may complete several generations in the succulent cells of the cortex layer of leaf or bulb tissues of garlic and onions. The fourth-stage juveniles of Ditylenchus sp. are known to withstand desiccation conditions,
Kata kunci: bawang, laporan pertama, nematoda umbi their condition make they survive for several years in the dry state in infected plant tissues or free in soil. Stem and bulb nematodes can spread mainly by infected seeds and planting materials, contaminated equipment, and other means of transporting infested soil. Economic thresholds of D. dipsaci are very low, each 10 nematodes per 0.5 kg of soil may caused to significant crop losses (Subbotin et al., 2005). Observation of the presence of stem and bulb nematode in Indonesia should be undertaken in an attempt to anticipate nematode attacks and in support to the national program of onion production

Observation and Nematodes Analysis
Observation was conducted in seed breeding areas in Temanggung, Central Java, Indonesia. Plants with exhibited specific symptoms of nematode damage such as leaf yellowing, declining and poor development plant were collected. Nematode samples were analized from soil rizhosphere, bulbs plant and infected roots. Isolation and extraction of nematode from both of soil and plant material were done by using Whitehead tray method modification referring to Southey (1986).

Nematode Identification
Identification was done based on morphological and morphometry caracters of nematodes. Male dan female adult specimens for microscopic observation were killed by gentle heat, fixed in FAA solution according to Seinhorst's method (Hooper, 1986). Specimens were obseved by light microscope Olympus CX 31 with magnification 40−1000×.
Measurements and drawings of specimens were made using a camera lucida which connected to microscope Olympus BH2. The observation of morphological and morphometrical of each speciment was done and referenced to related published data for identification to species level.

RESULTS AND DISCUSSION
The observation showed that the stem and bulb nematodes were found and attacks some varietes of garlic. Seven from nine location of garlic plantation were positifly infected by these nematodes (Table 1). Infected plants of garlic showed yellowing, stunting and twisting symptoms (Figure 1). Growth reduction was also observed in infested fields ( Figure 1C).
Infested bulbs are necrotic and tend to be rot with dark to black colour and its become soft. D. dipsaci for the first time found in garlic plantation in Temanggung, Central Java, Indonesia. Observation showed Ditylenchus dipsaci attacked were distributed on some location (Table 1). The population are range in average 2.67 nematodes per 100 g of soil and 2.67−189.33 per bulb. Nematode D. dipsaci is found at various altitudes and infects some varieties of garlic. The existence of the nematode is long time enough. As the same with the existence of potato cyst nematodes case in Indonesia (Indarti et al., 2004), these nematode already established for several years and bulbs possible to carry the imported seeds. Therefore, it's needed further study to know the origin of these nematodes.
Based on symptoms of infected garlic, nematode morphological characters of both female and male and also were supported with morphometric data, it's conclusion that species of plant parasitic nematodes which infect garlic in Temanggung, Central Java, Indonesia is Ditylenchus dipsaci.